Telescopic Steering Shaft Structure for Collision Collapse
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Solution Overview
Problem
Conventional vehicle steering apparatuses have limited intermediate shaft contraction during collisions, making it difficult to absorb collision energy and complicating assembly processes due to the large volume of the shaft.
Innovation Solution
The design includes a shaft member with a yoke and outer members featuring axial grooves and serration portions, allowing for increased contraction and axial extension, facilitating collapse and assembly by reducing the shaft's volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the intermediate shaft uses a conventional sliding structure with outer and inner members, then the shaft can be extended or contracted, but the contraction amount is limited to half of the remaining length excluding overlapping length, making it difficult to absorb collision energy
Solution Approach 1:
The intermediate shaft employs a nested telescopic structure where the first intermediate shaft is inserted into the second intermediate shaft, and the third intermediate shaft is inserted into the fourth intermediate shaft. During collision, these nested shafts can telescope inward significantly, achieving a contraction amount of 70-90% of the original length, thereby substantially improving collision energy absorption capability.
Solution Approach 2:
The intermediate shaft is divided into multiple segmented sections (first, second, third, and fourth intermediate shafts) that can move independently relative to each other. Each segment contains serration portions that engage during normal operation but allow controlled sliding during collision, enabling progressive collapse and energy absorption while maintaining structural integrity.
2Strength
If the intermediate shaft has a large volume to maintain structural integrity, then the shaft can withstand collision forces, but the movement of the intermediate shaft in assembly steps becomes inconvenient and the number of products supplied to the assembly line is reduced
Solution Approach 1:
The telescopic nested structure allows the intermediate shaft to be compacted to a fraction of its original volume during storage and assembly. When not in use, the shaft sections telescope inward, reducing the overall length and volume, which facilitates easier handling, movement, and assembly operations while maintaining full structural integrity when deployed.
3Strength
If the intermediate shaft has a large volume, then the shaft maintains sufficient strength, but the amount of products supplied to the assembly line is small, increasing the number of assembly steps
Solution Approach 1:
The telescopic nested structure enables the intermediate shaft to be stored in a compact form, significantly reducing the space required for storage and transportation. This allows more units to be stored and supplied to the assembly line simultaneously, thereby increasing productivity and reducing the number of assembly steps required.
Data Source
AI summary
A steering apparatus for a vehicle includes a shaft member having several outer axial grooves provided on an outer circumferential surface of a sliding section; a first outer member having a hollow shape; and a second outer member having a hollow shape. The first outer member has first serration portions axially formed on an outer circumferential surface thereof and several inner axial grooves formed on an inner circumferential surface thereof to correspond to the outer axial grooves of the shaft member. The second outer member has second serration portions axially provided on an inner circumferential surface thereof to correspond to the first serration portions of the first outer member.